Fuel control for turbine driven compressor unit



l. E. SPEER 3,002,346

FUEL CONTROL FOR TURBINE DRIVEN COMPRESSOR UNIT Oct. 3, 1961 s Sheets-Shet 1 Original Filed Feb. 8, 1951 ATMOSPHERE VENT /VA/V aspen,

IN VEN TOR.

l. E. SPEER 3,002,346

FUEL CONTROL FOR TURBINE DRIVEN- COMPRESSOR UNIT Oct. 3, 1961 3 Sheets-Sheet 2 Original Filed Feb. 8, 195] lOlx 90u- ATMOSPHERE VENT IVAN E. SPEER INVENTOk.

Vlllll mm fllllld I. E. SPEER 3,002,346 FUEL CONTROL FOR TURBINE DRIVEN COMPRESSOR UNIT Oct. 3, 1961 3 Sheets-Sheet 3 Original Filed Feb. 8, 1951 ENGINE STARTER VALVE ACTUATIN G MECHAN PNEUMATIC SWITCH AIR I IVA/V E. SPEER, INVEN TOR Unite States 3,002,346 Ce Patented Oct. 3, 1961 3,002,346 FUEL CONTROL FOR TURBINE DRIVEN COMPRESSOR UNIT Ivan E. Speer, Phoenix, Ariz., assignor to The Garrett Corporation, Los Angeles, Calif., a corporation of Cahfornia Original application Feb. 8, 1951, Ser. No. 209,929, now Patent No. 2,763,985, dated 'Sept. 25, 1956. Divided and this application Sept. 7, 1956, Ser. No. 608,555 14 Claims. (Cl. 60--39.07)

The present invention relates generally to apparatus for supplying a fluid such as air to a point of use for power and other purposes; it is more particularly concerned with a packaged unit which may be utilized in aircraft. In this connection, the apparatus is especially adapted for supplying air to pneumatic starters for turbo-jet and turboprop engines, as well as other types of engines utilized for the main propulsion power of aircraft.

This application is a true division of my co-pending application, Serial No. 209,929, filed February 8, 1951, and entitled Fuel Control for Turbine Driven Compressor Unit, now Patent No. 2,763,985.

One object of the herein described invention is to provide reliable apparatus for the required purpose, which is of low weight and bulk, and wherein the various components are assembled so as to form an easily installed and easily removable packaged power unit, containing the required essential auxiliaries and controls for its operation. I

It is a further object to provide an airborne air supply unit which is especially adapted to furnish air to a pneumatic starter, and wherein a novel dual bleed system is utilized for controlling the temperature of supplied air over a wide range of ambient temperature conditions, thus permitting attainment of aerodynamically matched conditions between the air supply unit and engine starter without the use of waste energy controls.

A further object is to provide apackaged power unit in which a gas turbine is utilized for driving a compressor which furnishes the combustion air for the turbine, and in which distributed air for power purposes is bled from the compressor outlet and proportionally mixed with hot turbine gases bled from the turbine inlet in such amounts as to control the bleed air energy level according to a predetermined schedule.

Another object is to provide a novel governor control arrangement in connection with a fluid supply unit of the character described herein, which modulates a fuel supply valve and is operatively associated with acceleration and high turbine exhaust temperature controls which are so arranged as to modify the normal fuel valve opera tion.

Still another object is to provide in connection with such a unit novel means for unloading the unit during starting and idling periods, and for limiting the load which may be carried thereby so as to retain the operating characteristics within predetermined values.

It is also an object to provide novel automatic starting control for the fluid supply unit of the present invention, making use of novel electric switching means arranged to be energized from compressor outlet pressure, and having circuit controlling contacts which are sequentially operable at low pressure, high pressure, and very high pressure.

Briefly, the packaged power unit of the present invention comprises a hot gas turbine which is axially aligned with and closely coupled to a compressor, with an intermediate accessory housing, the entire assemblage being mounted in an enclosing casing. The outlet of the compressor is connected with a suitable combustion chamber leading to the turbine inlet, and an air supply duct connects with the turbine inlet and compressor outlet through bleed connections which permit the dual bleeding of compressor air and hot turbine gases which by suitable apportioning control permit the delivery of the mixed fluid to the point of use at a desired energy level determined by the differential temperature betwen the ambient inlet air to the compressor and the temperature in the delivery duct.

The operation of the unit is normally regulated by a suitable governor, in this case a pneumatic control governor which is responsive to variations in ratio of com,- pressor inlet and outlet pressures, the normal regulation of the governor in the control of fuel supply being augmented by acceleration control means during starting of the unit, and by turbine exhaust temperature responsive means during operation of the unit. Unloading and load limiting controls are provided for regulating the supply of fluid delivered to the point of use, and consequently the operating characteristics of the unit. The electrical control is arranged for switch button start and stop' from a remote control station, the control being timed in accordance with the starting acceleration of the unit through the use of a pressure responsive switching device having sequentially operable contacts arranged to function at low pressure, high pressure, and very high pressure. Safety controls are also provided for overspeed.

Further objects of invention will be brought out in the following part of the specification, wherein detailed description is for the purpose of fully disclosing the invention without placing limitations thereon.

Referring to the accompanying drawings, which are for illustrative purposes only:

FIG. 1 is an isometric view ot a packaged power unit embodying the features of the present invention, looking at the compressor inlet end, portions of the casing and trate thermally controlled valves as utilized in the present invention.

The packaged unit in general Referring generally to FIGURES l and 2 of the drawings, the pack-aged power unit of the present invention is illustrated as having its component parts compactly assembled within an enclosing casing as generally indicated at 10 which terminates in end walls 11 and 12, respectively, and in which the necessary connections are mounted to permit the unit to be quickly and easily installed or removed.

Within the casing, an air compressor 13' is interconnected with an axially aligned hot gas turbine 14, a housing 15 for associated accessories being interposed between the compressor and turbine. I

Inlet air to the compressor is through a tubular inlet 16' which is mounted in the end wall 11 of the casing. Compressed air is conducted from the compressor through an outlet connection 17 tothe inlet of a combustion chamber 18 of the straight through type, the outlet end of this combustion'chamber connecting with the turbine inlet. Exhaust from the turbine is through an outlet 19 mounted in the end Wall 1 2 of the casing.

Combustion air in the combustion chamber is ad mitted through a perforated flame tube 20 and with a suitable fuel conducted into the combustion chamber through a supply conduit 21 and fixed area fuel nozzle 22. The fuel mixture is initially ignited by meansof a suitable spark plug which may be disconnected once the unit has been properly started.

A distribution duct 24, for supplying compressed air to .a point of use, isbroug'ht out through a tubular connection in the end Wall 12 of the casing. The compressed air supplied through the duct 24 is a mixture of bleed air taken from the compressor and combustion chamberdischar ges. The hotgases are supplied through a bleed connection 25 of fixed area, while the relatively cooler air from the compressor is supplied through a bleed connection 26, so that a by-pass in effect is formed around the combustion chamber 18. The temperature of air delivered to the distribution duct 24 is controlled by means of a modulating valve 27 which is mounted in the bleed connection 26. The actuating mechanism 27a of this valve is pneumatically controlled, air pres- .sure acting to open the valve and a spring acting to bias the valve towards closed position. Between the modu lating valve 27 and the inlet end of bleed connection 2 6, the bleed connectionisprovided with a branch conduit 28 which is connected with atmosphere and controlled by means of an unloading valve 29 arranged to be opened by the air .pressure in the conduit 23, and actuated to closed position by the application of air pressure in its control mechanism.

Within the auxiliary housing 15, provision is made for mechanically driving a fuel pump 30, oil pump 31 and scavenger oil pump 32 through suitable transmission gearing 33 by the turbine of the unit, oil being supplied through a closed system from an oil tank 34 having an exteriorly accessible filler connection 35 at the turbine exhaust end of the casing 10. The unit is arranged to be initially started and brought up to operating speed by means of a starting motor 36 forming a part of the electrical stunting and control system which will hereinafter be described in detail.

Fuel and oil systems As schematically illustrated in FIG. 3, the fuel system is a simple single flow line in which a supply conduit 37 connects with theinlet of the fuel pump 30, and an outlet connection 38 connects with the fuel supply conduit 21 of the combustion chamber. A filter 39 in the fuel pump discharge connection protects the fuel system of the unit, and a solenoid actuated shut-ofli valve 40, controlled as a "part of the electric starting and control system to be hereinafter described, controls the fuel flow when starting and stopping the unit.

Fuel metering and control is accomplished by a bypass valve 41 in a bypass connection 42 around the pump. The by-pass valve is arranged to be opened by fuel pressure from the discharge side of the fuel pump, and closed by air pressure under the control of a pneumatic governor 43 which is mounted in the air intake to thecompressor 13. As a safety measure, the fuel system is protected against abnormally high pressure by providing a pump by-pass connection 44 which is independently controlled by a relief valve 4 5. By-passed fuel'inboth by-pass 4-2 and by- 'pass 4-4 will be returned to the pump inlet.

The oil system is a positive pressure circulating oil system in which the oil supply is contained within the oil tank 34. Oil is pumped by the oil pump 31 from the oil tank and delivered under pressure to the unit, and is'returned to the tank by means of the scavenger oil pump 32, an oil filter 46 being placed in the return line. As a safety measure, a connection 47 is provided between the discharge side of oil pump 31 and the return oil line from the scavenger oil pump 32, this conmotion-being normally closed by means of a relief valve 48.;

Electrical starting and control system Provision is made for carrying out the automatic starting and ignition, and the various steps are properly coordinated and sequentially effected upon the closing of a starting switch 49 having normally open contacts 50a and 50b. This switch as well as a stop switch 51 having normally closed contacts 52 may be mounted at a remote station such as the pilots or flight engineers station and may also include indicating l amps, as illustrated at 53, as necessary.

The starting motor 36 is controlled through a starting relay 54 having an actuating coil 55 and normally open contacts 56a and 5617. An interlocking and overspeed relay 56 contains normally open contacts '57 and an actuating coil 58, one side of this coil being connected with the ground side of the current source by a conductor 59 thrcughnormally closed contacts 60 of an overspeed switch 61. The relay 56 may be housed within a control box 62, as shown in FIG. 1, support-ed upon the intermediate auxiliary housing 15. Positioned adjacent the control box 62 is a pneumatically operated switch 63 which is connected through a conduit '64 to the compressor outlet so as to sense the compressorout let pressure. This switch is arranged so as to sequentially close low pressure contacts, high pressure contacts, and very high pressure contacts. The low pressure contacts comprise normally open contacts 64a and normally closed contacts 64b. The high pressure contacts comprise normally closed contacts 65a and 65b, whereas the very high pressure comprises normally open contacts 66.

The operation of the electrical starting and control system will now be described. A suitable source of electric control current is provided, .and may be from a suit able battery or generator, the source in the present instance being indicated by the numeral 67 with one side grounded.

In order to start the unit, it is only necessary to depress the starting switch '49 so as to close its contacts. The starting motor 36 will now be energized by activation of the starting relay 54 through the following circuit: from one side of the electrical source 67 through contacts 50!), conductor 68, closed contacts 64b, conductor 69, contacts 52 of the stop switch, through conductor '70, contacts 59a, through conductor 71 to one side. of coil 55, and from the other side of this coil to ground. Energization of relay 54 causes it to close its contacts 56a and 56b. Closing of contacts 56a connects the starting motor 36 directly to the electrical source.

The relay 56, having one side of its actuating coil 58 connected through conductor 72 with the energized conductor 69, will be energized, since the other side of its coil is connected through conductor 59 .and contact of the overspeed switch to ground or the other side of the circuit. Relay 56 now closes its contacts 57 which enables release of the starting switch by establishing a holding circuit on the starting relay as follows: from one side of the electrical circuit'67 through line 75, contacts .57, conductor 73, the closed contacts 65a of the .jpneu matic switch, conductor 74, contacts 56b, and thence by conductor 71 through the coil 55 and to the other side of the electrical circuit.

The starting motor 36 will now continue to accelerate the unit, and when the rotating speed becomes sufficiently high to produce the necessary pressure in the combustion chamber for ignition, the low pressure contacts of the pneumatic switch 63 will be actuated from'their normal positions so as to close contacts 64a and open contacts 64b whereby to energize the solenoid shut-oil valve 40 to supply fuel to the combustion chamber, and energize the spark plug 23 for igniting this fuel. The solenoid shutoff valve is energized through the fol-lowing circuit: from the high side of the electrical source 67, through conductor 75, contacts 57, conductor '73, contacts 52, conductor 69,'the now closed .contactsfla,

stage is conductor 76 and conductor 77 to one side of the solenoid valve 40, and from the other side of this valve to the grounded side of the electrical source. The spark plug is energized through a branch connection of conductor 76 which passes through normally closed contacts 65b of the pneumatic switch 63, thence through conductor 78 to an ignition coil 79 having a grounded connection.

After the unit has accelerated to suflicient speed to support itself, the pneumatic switch 63 opens its high pressure contacts 65a and 65b which open the holding circuit of the starting relay 54 to disconnect the starting motor, and disconnects the ignition coil 79 which energizes the spark plug. The unit then accelerates to an operating condition at which the governor control takes over, as will hereinafter be explained in detail.

In the event that the compressor outlet pressure should reach a predetermined value of very high pressure, provision is made for indicating this condition to the remote control station. Such pressure will cause the pneumatic switch 63 to close its contacts 66 which will connect a branch of conductor 76 to conductor 80 which is connected to one side of signal lamp 53, the other side of this lamp being connected to the grounded side of an electrical source.

During normal operation, it will be observed that the energizing circuit of the solenoid shut-01f valve 40 is through the contacts 57 of relay 56. Should an overspeed occur, which will open contacts 60, the energizing circuit to the coil 58 will be interrupted and permit this relay to open its contacts and enable closure of shut-ofi valve 40 to stop the unit. The unit may also be stopped by actuation of stop switch 51 which will open its contacts and also interrupt the energizing circuit of the coil 58 of relay 56, whereupon the relay will open its contacts to shut down the unit in the same manner as just explained.

Pneumatic control system In its broad concept, the present invention contemplates that various types of governors may be utilized for normally controlling the unit of the present invention, such as a mechanical inertia type of governor, a hydraulically actuated governor and pneumatically controlled governor. For purposes of illustration and discussion, a pneumatic governor is utilized in connection with the pneumatic control system. This governor, as will be noted in FIGURE 3, is mounted at the inlet of the compressor 13 and is connected through a conduit 81 and filter 82 with conduit 64 which senses the compressor outlet pressure. This governor, as diagrammatically shown in FIG. 4, is arranged to modulate the supply of air pressure to conduit 83, the conduit 83 being connected through a branch connection 84 with the air pressure side of the by-pass valve 41 control. Air flow from conduit 81 to conduit 83 is controlled by a valve 81a operatively connected to a movable wall or diaphragm 82a subject on one side to compressor outlet pressure and on the other side to compressor inlet or atmospheric pressure, so that fuel supply will be varied directly in response to variations in the compressor inlet pressure. For example, if the compressor inlet air pressure decreases, the fuel supply will likewise be decreased. The governor 43 is thus basically arranged to control the unit to a constant compressor pressure ratio over the load range thereon. Thus, by varying the air pressure acting on the by-pass valve 41, the fuel supply to the combustion chamber is properly controlled.

A metering orifice 85 bleeds fluid from the conduit 83 to the atmosphere at a restricted rate, and thus permits the pressure in the conduit to be reduced after valve 41 has been closed. When the pressure in conduit 83 is reduced, fuel pressure from pump 30 will open valve 41 to bypass fuel.

Provision is made for modifying the normal governor control upon the occurrence of predetermined overtemperature in the turbine exhaust. For such purpose,

there is provided a pressure vent valve 86 having a temperature sensing control element. This valve is connected by branch conduit 87 with conduit 83 so that at high temperature, the pressure in line 83 will be reduced so as to permit greater by-pass of fuel through by-pass valve 41, whereupon the fuel furnished the combustion chamber will be reduced and the exhaust gas temperature lowered. As diagrammatically shown in FIG. 5, the vent valve 86 briefly comprises a housing having a tubular portion 86a within which there is mounted a rod 87a, these parts coacting to provide temperature responsive means in a manner well known in the art. Spring mounted valves 88a and 88b, carried by the rod are operatively associated with valve seats 89a and 89b connected respectively with conduits 87 and 100. The arrangement is such that as the temperature of the tubular portion and rod increases, the valves will be moved towards open position. The valve housing is vented to atmosphere at 96a.

It will be appreciated that there will be some time lag in the operation of the vent valve 86. During starting of the unit, prior to the time when the governor control takes over, the fuel pump tends to furnish a greater amount of fuel than required. In order to reduce the fuel supply during acceleration of the unit, an acceleration control valve 88 is provided for normally bleeding air from conduit 83 through a restricted orifice 89 and atmospheric through a normally closed solenoid operated cut-oh valve 93 to a distribution control pressure conduit 94 which may lead to a remote pneumatic control station, in this instance a control station for an engine starter 95 connected to receive operating air from the distribution conduit 24. The cut-off valve 93 may therefore be utilized to initiate supply of air to a remote point of use, and as a consequence the loading of the unit. The conduit 94, it will be observed, is connected to the pressure closing side of the unloading valve 29, so that upon initiating control which will result in loading of the unit, the unloading valve will be closed to shut off flow through the conduit 28. Since the conduit 91 is also connected to distribution conduit 94, the placing of pressure on conduit 94 will also result in closing the acceleration control valve 88.

A load limiting valve 96 is mounted in the distribution duct 24. In practice, this valve, as well as a thermally controlled valve 97 is preferably connected to the end of the duct 24, which is shown in FIGURE 2 as projecting from the casing end wall 12, in order to prevent time lag in operation. The valve 96 is operated by an actuating mechanism 98a which is spring operated in a valve closing direction and by pressure from conduit 98 in a valve opening direction, the conduit 98 being connected to conduit 92 through a metering orifice 99 which limits the pressure supply from the conduit 92 and permits actuation of the load limiting valve by bleeding oif air from conduit 98 through connection conduit 100 at a predetermined temperature setting of pressure vent valve 86.

Since the power available from expansion of compressed air supplied from the unit varies directly as the temperature of the source, it is contemplated in the present invention to control the temperature according to a predetermined schedule. The bleed air temperature furnished through the duct 24 is controlled to a constant increase above ambient by mixing combustion gases with the compressor discharge bleed air. The mixing of bleed air and hot gases is accomplished through the operation of the modulating valve 27 which is operatively arranged to be spring closed and pneumatically opened. Pressure for actuating the valve 27 is controlled through a thermally controlled valve 101 located in the compressor inlet at the end of a conduit 1&2, this valve being arranged to vent the conduit to atmosphere in response to temperature changes in ambient air entering the compressor. Operating air pressure is normally supplied to the conduit 102 from conduit $4 which is connected through conduit 103 andthe thermally controlled valve 97 to the conduit 102. A branch conduit 104 connects conduit 192 with the actuating mechanism of valve 27. The valves 97 and '101-are both arranged to open when the associated temperature increases and are in general of similar construction to that of valve 36 previously described. As diagrammatically shown in FIG. 6, the valve 97 is in this case notvented to atmosphere and contains only the valve 88a, the seat 89a in this case being connected to conduit 103, While the seat 8% is in this case connected to conduit 192. On the other hand, valve 101, as shown in FIG. 7, is vented to atmosphere and the valve seat 89a is in this case connected to conduit 182, the valve seat 8% and its conduit connection being eliminated. With the arrangement just described, it will be apparent that if the temperature at the valve 97 increases too high, this valve opens and increases the pressure acting in the conduit 104, thus actuating valve 27 toward open position so as to supply a greater amount of compressor outlet air through the bleed connection 26 for restoring the temperature to normal. A decrease in temperature at the valve 97 acts conversely to close the valve 27 and cause the temperature to be increased toward normal condition.

At the intake of the compressor, the valve 101, upon increased ambient temperature, will open so as to vent the conduit 192 and thus decrease the pressure acting upon the operating mechanism of valve 27, thus enabling this valve to move towards closed position under its spring action. This will decrease the flow of relatively cooler air through the bleed connection 26 and enable the hot turbine gases from bleed connection 25 to raise the temperature at valve 97 so as to restore the proper pressure differential between the temperature at valve 97 and the ambient air temperature at valve 101. With a decrease of ambient temperature at valve 191, the operation will be just the opposite.

It will therefore be apparent that by controlling the modulating valve 27 in the manner described above, a scheduled temperature diflerential may be maintained between the temperature of delivered air through the duct 24 and the temperature of ambient air entering the compressor 13. In the case of the utilization of the herein described unit to supply operating air pressure to an engine starting turbine 95, this arrangement permits aerodynamically matched operation of the turbine compressor unit and the air starter through a wide range of ambient temperatures without the use of waste energy controls.

It will also be appreciated that a power packaged unit of the herein described construction may be utilized to selectively furnish through proper selective valves operative air pressure to a plurality of starting turbines.

Itais appreciated that various modifications may suggest themselves to those skilled in the art without departing from the spirit of the present invention, and, hence, it is desired that the invention shall not be restricted to the specific form shown or uses mentioned, except to the extent indicated in the appended claims.

I claim:

1. A fluid supply unit, comprising: a gas turbine including a combustion chamber; a compressor driven by said turbine having an outlet connected to said combustion chamber; a by-pass around said combustion chamber; a fluid distribution bleed air connection with said by-pass; and pressure responsive means controlled by ompressor inlet and bleed air temperature for apportioning fluid flow through said by-pass.

2. Apparatus for supplying a heated fluid to a point of use, comp-rising: a gas turbine including a combustion chamber connected to its inlet; a fluid compressor driven by said turbine and having an outlet connected to said combustion chamber; a distribution duct having a connection for bleeding compressor outlet fluid and a connection for bleeding turbine inlet fluid; and bleed flow temperature control means responsive to variations in temperature differential between the fluid in said distribution duct and the inlet fluid to said compressor including a valve in at least one of said connections.

3. Apparatus for supplying fluid at a controlled tempenature comprising: a gas turbine having a combustion chamber connected to its inlet; a fluid compressor driven by said turbine and having an outlet connected to said combustion chamber; a distribution duct having a. connection for bleeding compressor outlet fluid and a connection for bleeding turbine inlet fluid; valve means communicating with at least one of said connections to control fluid flow therethrough; and means for operating said valve means in response to predetermined temperature variations in at least one location including the distribution duct and compressor inlet.

4. Apparatus for supplying fluid at a controlled temperature comprising: a gas turbine having a combustion chamber connected to its inlet; a fluid compressor driven by said turbine and having an outlet connected to said combustion chamber; a distribution duct having a connection for bleeding compressor outlet fluid and a connection for bleeding turbine inlet fluid; valve means communicating with at least one of said connections to control fluid flow therethrough; and means for adjusting said valve means to modulate the temperature in said distribution duct, said means having thermo-respousive elements in said distribution duct and in said compressor inlet bot-h operatively connected with said valve adjusting means.

5. Apparatus for supplying fluid at a controlled temperature comprising: a gas turbine having a combustion chamber connected to its inlet; a fluid compressor driven by said turbine and having an outlet connected to said combustion chamber; a distribution duct having a connection for bleeding compressor outlet fluid and a connection for bleeding turbine inlet fluid; valve means communicating with at least one of said connections to control fluid flow therethrough; means for adjusting said valve means to modulate the temperature in said distribution duct, said means having thermo-responsive elements in said distribution duct and in said com-pressor inlet both operatively connected with said valve adjusting means; a second valve means in said distribution duct for controlling fluid flow therethrough; and means for actuating said second valve means, said actuating means having a thermo-responsive element in the turbine exhaust operatively connected with such actuating means.

6. Apparatus for supplying fluid at a controlled temperature comprising: a gas turbine having a combustion chamber connected to its inlet; a fluid compressor driven by said turbine and having an outlet connected to said combustion chamber; a distribution duct having a connection for bleeding compressor outlet fluid and a connection for bleeding turbine inlet fluid; valve means communicating with at least one of said connections to control fluid flow therethrough; means for operating said valve means in response to predetermined temperature variations in at least one location including the distribution duct and the compressor inlet; a branch bleed duct extending from one of said connections; and pressure responsive means for controlling fluid flow through said branch bleed duct.

7. Apparatus for supplying fluid at a controlled temperature comprising: a gas turbine having a combustion chamber connected to its inlet; a fluid compressor driven by said turbine and having an outlet connected to said combustion chamber; a distribution duct having a connection for bleeding compressor outlet fluid and a connection for bleeding turbine inlet fluid; a load limiting valve in said distribution duct downstream from the turbine inlet fluid bleeding connection; and means for closing said load limiting valve in response to predetermined temperature increase in the turbine outlet.

8. Apparatus for supplying fluid at a controlled temperature comprising: a gas turbine having a combustion chamber connected to its inlet; a fluid compressor driven by said turbine and having an outlet connected to said combustion chamber; a distribution duct having a connection for bleeding compressor outlet fluid and a connection for bleeding turbine inlet fluid; valve means communicating with at least one of said connections to control fluid flow therethrough; means for operating said valve means in response to predetermined temperature variations in at least one location including the distribution duct and the compressor inlet; a load limiting valve in said distribution duct; and means for operating said load limiting valve in response to predetermined temperature variations in the turbine outlet.

9. Apparatus for supplying fluid at a controlled temperature comprising: a gas turbine having a combustion chamber connected to its inlet; a fluid compressor driven by said turbine and having an outlet connected to said combustion chamber; means for directing fuel to said combustion chamber; a fuel control valve in said means; a distribution duct having one connection for bleeding fluid from said compressor outlet and a second connection for bleeding fluid from said turbine inlet; valve means communicating With at least one of said connections to control fluid flow therethrough; and means for operating said fuel control valve and said valve means in response to predetermined temperature variations in at least one location of the group including the distribution duct and the compressor inlet.

10. Apparatus for supplying fluid at a controlled tem perature comprising: a gas turbine having a combustion chamber connected to its inlet; a fluid compressor driven by said turbine and having an outlet connected to said combustion chamber; means for directing fuel to said combustion chamber; a fuel control valve in said means;

a distribution duct having one connection for bleeding fluid from said compressor outlet and a second connection for bleeding fluid from said turbine inlet; valve means communicating with at least one of said connections to control fluid flow therethrough; means for operating said fuel control valve and said valve means in response to predetermined temperature variations in at least one location of a group including the distribution duct and the compressor inlet; a load limiting valve in said distribution duct; and means for operating said load limiting valve in response to predetermined temperature variations in the turbine outlet.

11. Apparatus for supplying fluid at a controlled temperature comprising: a gas turbine having a combustor connected to its inlet; a fluid compressor driven by said turbine and having an outlet communicating with said combustor; a distribution duct having a connection for bleeding compressor outlet fluid and a connection for bleeding turbine inlet fluid; a fluid pressure responsive load limiting valve in said distribution duct downstream from the turbine inlet fluid bleeding connection; passage means leading from a source of fluid pressure to said load limiting valve; and valve means in said passage and responsive to an increase in turbine outlet temperatures to control flow of fluid pressure to said load limiting valve to eflect a closing operation thereof.

12. Apparatus for supplying fluid at a controlled temperature comprising: a gas turbine having a combustor connected to its inlet; a fluid compressor driven by said turbine and having an outlet communicating with said combustor; a distribution duct having a connection for bleeding compressor outlet fluid and a connection for bleeding turbine inlet fluid; a bleed air temperature modulating valve in one of said connections, said modulating valve being responsive to fluid pressure; passage means leading from a source of fluid pressure to said modulating valve; valve means communicating with said passage means, said valve means being responsive to temperatures in said compressor inlet and a portion of said distribution duct to control the application of fluid pressure to said modulating valve.

13. Apparatus for supplying fluid at a controlled temperature comprising: a gas turbine having a combustor connected to its inlet; a'fluid compressor driven by said turbine and having an outlet communicating with said combustor; a distribution duct having a connection for bleeding compressor outlet'fluid and a connection for bleeding turbine inlet fluid; a bleed air temperature modulating valve in said distribution duct between the connections for compressor outlet and turbine inlet fluid therewith, said modulating valve being responsive to fluid pressure; a load limiting valve in said distribution duct at the downstream side of the turbine inlet fluid bleed connection, said load limiting valve being responsive to fluid pressure; passage means leading from a source of fluid pressure to said temperature modulating and load limiting valves; and control valve means communicating with said passage means, said control valve means being responsive to predetermined turbine and compressor operating conditions to control the application of fluid pressures to said temperature modulating and load limiting valves to effect the operation thereof.

14. Apparatus for supplying fluid at a controlled temperature comprising: a gas turbine having a combustor connected to its inlet; a fluid compressor driven by said turbine and having an outlet communicating with said combustor; a distribution duct having a connection for bleeding compressor outlet fluid and a connection for bleeding turbine inlet fluid; a bleed air temperature modulating valve in said distribution duct between the connections for compressor outlet and turbine inlet fluid therewith, said modulating valve being responsive to fluid pressure; a load limiting valve in said distribution duct at the downstream side of the turbine inlet fluid bleed connection, said load limiting valve being responsive to fluid pressure; passage means leading from a source of fluid pressure to said temperature modulating and load limiting valves; a first control valve means communicating with a part of said passage means, said first control valve means being responsive to combinations of temperatures at the compressor inlet and in said distribution duct at the downstream side of said turbine inlet fluid connection to control the application of fluid pressure to said temperature modulating valve to effect the operation thereof; and a second control valve means communicating with another part of said passage means, said second control valve means being responsive to temperatures in the tur bine exhaust to control the application of fluid pressure to said load limiting valve to effect its operation.

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